package com.wangjw.leetcode;

import java.util.Stack;

/**
 * Created by wangjw on 18/5/1.
 */
public class LeetCode20 {

    public boolean isValid(String s) {
        Stack<Character> stack = new Stack<>();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == '(' || c == '[' || c == '{') {
                stack.push(c);
            } else {
                if (stack.isEmpty()) {
                    return false;
                }

                char topChar = stack.pop();
                if (c == ')' && topChar != '(') {
                    return false;
                }
                if (c == ']' && topChar != '[') {
                    return false;
                }
                if (c == '}' && topChar != '{') {
                    return false;
                }
            }
        }
        return stack.isEmpty();
    }

    public static void main(String[] args) {
        System.out.println(new LeetCode20().isValid("()[]{}"));
        System.out.println(new LeetCode20().isValid("([)]"));
    }
}
